Method of making building material



March 23, 1954 E. T. RHODES METHOD OF MAKING BUILDING MATERIAL Filed Feb. 18, 1949 Patented Mar. 23, 1954 UNITED STATES PATENT OFFICE METHOD 0F MAKING BUILDING MATERIAL Eugene T. Rhodes, Brentwood, Mo. Application February 18, 1949, Serial No. 77,170

(Cl. .Z5- 155) 5 Claims.

The present invention relates to a method of making building material.

As will appear from the description to follow, the present invention is concerned particularly with making a very strong building slab of great density and very low absorption characteristics. It will be understood also from the description that the method, although preferably employed to make a building slab that is relatively thin and maybe used for external sheeting or veneering, it also can produce other shapes of building mate-- rial of succative, cohesive material, such as blocks andthe like. Hence, while the description will proceed by a complete disclosure of the method of making a slab that is relatively thin, and the slab made by the method, it must be borne in mind that the use of the invention in the pro duction of other shapes or blocks of construction material is contemplated.

Heretofore, building material of this kind has :w

durability that are attained by the present invention.

Furthermore, with specific reference to the slab type of construction, it is a desirable feature of this invention that facing slabs may be made for application to new or old buildings, which facing slabs produce in over-all effect that of a brick or stone building, whereas actually they are of a veneer construction that is very much cheaper to build and which has insulation properties that are superior to solid masonry construction, as well as a great deal less expensive to build.

It is another object of the invention to produce such a material with facing integrally formed therewith; and to provide a method whereby such unit of facing and backing material may be formed as a single process.

In the drawings:

Fig. 1 is an elevation of a slab made in accordance with the present invention;

Fig. 2 is an edge view of the slab, taken from above Fig. 1, as indicated at 2 2;

Fig. 3 is a section through the slab taken on the line 3-3 of Fig. 1;

Fig. 4 is a somewhat diagrammatic sectional f view of a stage in the molding of the material for the slab; and

Fig. 5 is a somewhat diagrammatic view of a later stage in the molding of the material for the slab. .L '.L

In the description to follow, explanation will be made of the formation of a at slab. It will be understood how other similar building elements may be made, by consideration of this particular illustration.

The slab of Fig. 1 is generally indicated at I0. It is here shown as having what may be termed a backing or base II of predetermined size that is illustrated as being of the size of a number of bricks and half bricks. Superposed onto the base I l are a plurality of portions of facing material I 2 that are, in the illustration, simulated bricks. In Fig. l, there are six full brick sections and four half brick sections. The base I I is cut back on two edges, as at I3 and I4, and overhangs on the other two edges, as at I5 and I 6, so that the slabs may be mounted on .a wall and overlapped. In other words, another slab like the one illustrated may be disposed above the one shown with the tongue I3 of the illustrated slab engaging within the groove or rabbet I6 of the one above. In like manner, another slab may be located to the right of that illustrated in Fig. 1, with its tongue I4 engaged within the rabbet I 5 of the slab shown in Fig. l. The parts may be attached to the Wall by suitable fastening means such as screws. The material has adequate strength to withstand the compressive forces of the screws and, as a result, an extremely strong wall may be obtained.

It is desirable, especially to enhance insulation qualities of a wall, to provide a plurality of recesses I8 in the back of the slab. These may be rectangular or of other suitable shape.

To make the slab, facing material, where used,

' is employed to simulate the color and texture of bricks, stones or whatever is desired. A preferred formulation of facing material to obtain a brick Iappearance is as follows:

The foregoing gives the preferred formulation. The granulars afford greater strength., toughness, and durability, and add to the permanency of color, particularly the reds and browns. The asbestos fiber is used as a reenforcement to add strength and flexibility to the product, and to add to its heat insulation quality, by counteracting the'thermal-conductivity of the cementA The pig- The granulars may be naturalrcolored granu. v

lars such as burnt shale or crushed monument granulars, all of a quality that willnotfade when exposed to Weather. The materialsshould pass, through a 2li-mesh screen. The asbestos fiber may be #7M short sold by Asbestos Corporation,t.

Ltd. It is preferable to employ short fibers in the facing,y which usually gist-disconnected.sections that do not require `great A,streng-slum Shorts afford easier'Workingggandl asner texture to the facing.

The facing materials are all put together linra dry; state `and thoroughly .mixed s while :still dry for a lperiodof about fifteen ;'minutes-,:-. preferably by whirling and .beating-J; This dry Vmixingforces the finer 3 particles -of` cement :into the Y loosely Wovemasebestos. bers. ing.a very fine-y spraybf, Water `is addedzwhile the mixing continuesfo,r-about arl-additional .ten minutes,until preferably-:about live percent by Weight of `water-has beenadded. Therange `.of water :preferably further is -about. .four tot seven percent-.1; After the .Waterahas- :been added,V the material is` then. runthrough a .#8 sieve,4 which actionleaves thelfacinggmaterialrin a fluffy loose state andfready to .be used.

The base. or backing gmaterials. preferably `include the following :y

60 1b. high earlycement, such as Portland or like hydraulic cement.;

10V lb. short asbestos fibers;

15 lb. long. asbestos fibers 15 1b, .ground limestone and..

2 lb. special `waterproofing compound.

The asbestosflbers may =fb #17M shortf and #522D long, obtained from AAsbestos' Corporation Ltd. The' -bers and cement func-tion 'irr the base 4material as `in the facing-material. The long fibers give great str'engthand flexibility in the backingmaterial, which carries-the-'maj-or part of the load. The ground-limestoneisdesirable because it acts as a good ller 4and also lendsexibility tothe treatedv slabs; The waterproofing compound may be the commercialI water proong compound of Medusa Cement Company. It is a desirable component, because it. provides awaterproof` 1end `product .after vthe .processing herein described is completedr vSuch waterproofing compounds usually last. from v,tvvo .to three years.. The present product continuesto cure for about. Ithe sameV length of.. time, and by theend of such interval it' attains a great. density' 'so that it is itself waterproof.

The. above forn'lulation:for:- the; :backing material isoptimum: However, a usableproduct may 'be obtained when the; cementvaries'fromi40e60i% ofthe totalyv the. .beritotal `variesvfrom 2Q-14G%.-;; and there limestone,` when;A used, varies from 1Q20'=%`.-i

Thesematerials arepu-t together-:inrafdry ,State Following the. dry

mxedfwhileedry .fora :period of aboutfteen .15

minutes, preferably by whirling and beating. During the dry mixing, the cement is forced into intimate mixture with the loosely Woven fibers of asbestos.

After the dry mixing period is finished, an additional period of about ten minutesis employed for the addition of Water. This Water is added during a continuation of the mixing operation by the use of a very fine spray. The amount of Water isV limt'edzto about three to'sevenl percent by weight, and preferably about three percent. In order to avoid the possibility of balling, the material after the Water is added is run through a1#3 power sieve,y vwhich leaves the material in a loose fluffy state.

In themolding operation illustrated here where facing materialis employed to simulate bricks, a press having a'bed member 20 and a head 2| is-i,.employed. The bed 20 has a cavity in which a pallet 22 istted. This pallet is preferably of relatively 1 light aluminurrr, It hason.. its upper face a mold cavity to shape the outer surfaces of.. the slab Thisincludes a.,plurality of.[ribs 23 that. correspondl with themortar joints` or spaces to :simulate mortar :joints ybetween the...several briclrsections.` The ribs separatey a :plurality Vof brick or y half brick cavities 24. The pallet ,is otherwise shaped. as indicated-to provides, final product of-fthe desired, previously described shape. -A framef25 .may beernployed on-,two.sides, to give thefbevelat thesentvvo .edges of. the. slab.

The A.press head 2i. is .adapted to. twithin the bed cavity and ,oveiuthepallet Y22, as-shoWnin Fig.; 5. The head 2i isshaped .to provide the back ofthe.. slab, and` includes a plurality of projections 26 tcform the recesses I8 yinthe back of the slab Hl. In the flrstmolding step, thefacing material-.preparadas aforesaid islledfinto ,the mold at least up to the tops of the ribs. 23,'v whichk may be fkeptclean by. aremovableternplate or thelike, or made .clean after this step` The facing materialmust be given a suitable depththat Will make it durable Whensubjected to thevveather.` Without. overly exposing thebasematerial. n

After .the facing ymaterials..are thusapplied, the base material is lled into the mold cavity. -to a suitable level,y such `baseimaterialy beingl sho-wn in `ligi ate.2l inrits fluffy state. The, depthis sufficient y,to assure-that,A Whenthe full pressure 4is applied ,to thebase fmaterial, .by `the press and thefpress. is sub-j ectedto molding. lforce inproper degree; ftheendproduct .will have approximately the -nal'thickness .of the slab.

In the: preferred operation, the base vmaterial, inits fluffy and semi-dry `state resulting :from the previous'description,-is1 lled yto'thetopof 4the mold cavity in the base 20, and scraped off. This cavityhasadepth `to assu-re: the-proper amount of fmaterial... For aslab having an yendthickness `ofabout 42"? including facingfin'its major area, and aboutgl for-the vmajor-part of the ybacking material, an ini-tial,=thickness,- of 'fluffy material of about 1l is desirable. With thinner sectionsthis ratio -of initial to final thicknessfmay `be reduced, but, with thicker-sections, it: will :be enlarged. z In generaL-.the ratio/should beV atl least; better than 2:1 and preferably atleast about-13:1..

When` the. proper. A'supply tofI fluffy material is added, the head 2l of the pressisbroughtidown,

preferably relativelyA fslowly; and the slightly .fully opened .position tof 'its'.l closed position to its fully opened position again. t

It is necessary to have a large force applied by the press. The unit pressure is preferably in the order of 1250 p. s. i., and at least about 750 p. s. i. The desirable characteristics in the end product are not obtained with a pressure of substantially less than 750 p. s. i.

When the press head 2l is subsequently withdrawn, the pallet 22 is ejected, ejecting pins 2t being diagrammatically shown. This pallet is then supporting the highly compressed, semi-dry, but still incohesive matter. The pallet with the material on it is placed on a drying rack. The material in the mold is then sprayed with a fine spray of water until thoroughly wet. About e of water is applied, which fills the cavities i8. The spraying of this water avoids damage to the incohesive cementitious compressed materials on the pallet. Then the pallet is allowed to stand for about twelve hours.

When the slabs are removed from the plates, they are immersed in water for about an hour. This may be done by a batch operation where a large number of such slabs, stacked on edge on properly formed racks, are immersed as a group. By this immersion, they take up an additional quantity of water that is necessary for the final curing operation. The preliminary setting operation that takes place during the twelve hour period in which the material remains on the pallet is sufcient to cause the slabs to set up to a permanent state so that they will not expand upon the nal submersion, and so that they will be quite adequately strong to be subjected to the final curing step that has been set forth. The iinal curing step takes place by withdrawing the slabs from the immersion tank and stacking them in place for about fifteen to twenty days so that the water may effect the cure and so that excess water may evaporate. At the end of such fteen or twenty days period, the slabs are then ready for use, being hard, tough and very dense.

A rule of thumb for testing the completeness of the nnal wetting operation is to observe when bubbling from the slabs stops. Generally for a slab of the illustrated type, an immersion of forty minutes to an hour is sunicient, but this varies somewhat with the atmospheric conditions and with the thickness of the sections.

The nal curing stage usually is finished within fteen days, where temperature and humidity are controlled. It should not be speeded up in a manner that will cause encrustation of the outer parts. For ordinary air curing, at about 65-70" F., a longer period is required.

To illustrate the relative density of the present slab with similar slabs made under other processes, comparative tests indicated that a slab made by the former process would have a forty percent absorption factor under certain circumstances, as compared to a twelve percent or less absorption factor of the present material.

It will be seen that the principal handling operations can al1 be done within a period of an hour or less, including the mixing, pressing and spraying for the preliminary curing operation.

The slabs, when removed from the pallets, will have the desired conguration, and, in the illustrated form, will have the facing material forming at least the outer surfaces of the bricklike sections l2. Obviously, different colors o facing materials may be used, and different shapes of facing materials. The familiar alternative to the brick configuration is the coniiguration of stone.

The foregoing superior product is provided by the process described, and the process obtains its result with a minimum number of steps. It is especially desirable to obtain the end product with integral facing by a single compression operation.

What is claimed is:

l. ln a method of making a building material: the steps oi mixing cement and compressible fibres into a loose, luify mass, the major part of the mass being cement; thoroughly distributing about 3%--7% by weight of water into the mass while maintaining it in its loose, fluffy state; shaping the same by compressing' it on a platen under pressure of at least about 750 p. s. i. to at most about one-third of its original thickness, and thereby producing a dense shaped mass that is too dry to be self-supporting; further wetting the mass while still on the platen and allowing it to stand for a period sufficient to cause it to become cohesive, thereafter iinally `wetting it thoroughly for a period of time to cure into a dense, monolithic mass.

2. The process of claim 1 wherein the further wetting of the material on the platen is preformed by a fine spray to aord even distribution and to avoid deformation of the mass on the platen.

3. The method of claim 1 in which the i'lbers are asbestos fibers.

4. The method of claim 1 wherein the cement comprises about 40%-60% by weight of the total, the fiber total Varies from about 20%-40%, and wherein there is a iller o ground limestone or the like that constitutes about l0%-2G% of the total.

5. The method of claim l including the formation of a layer at one surface thereof by thoroughly mixing granulare of about 10 %-40%, cement from about 30%-75%, fibers about l0%-20%, and the balance pigments, the percentages being by weight, said materials being thoroughly mixed while dry in a loose, fluffy state and then being moistened by the addition of about 4%7% of water, and thereafter being disposed as a loose, fluffy layer with the previously mentioned material of claim 1 and with said material is compressed and molded, wetted, caused to take up water, and cured in the manner set forth in claim 1.

EUGENE T. RHODES.

References Cited in the le of this patent UNTED STATES PATENTS Number Name Date 176,666 Mitchell Apr. 25, 1876 732,674 Bell et al June 30, 1903 1,395,990 Crawford Nov. 1, 1921 1,559,146 Andrews Oct. 27, 1925 1,678,346 Mattison July 24, 1928 1,704,193 Hoffman Mar. 5, 1929 1,796,631 Stryker, Jr Mar. 17, 1931 1,805,431 Ryder May 12, 1931 1,961,525 Offutt June 5, 1934 2,170,434 Siegle Aug. 22, 1939 2,246,537 Rembert June 24, 1941 2,383,736 Rembert et al. Aug. 28, 1945 2,407,514 Rernbert Sept. 10, 1946 FOREIGN PATENTS Number Country Date 13,452 Great Britain of 1901 

